Potential Quality Problems
As an energy-saving building material, insulated glass is widely used because of its good thermal and sound insulation properties. At the same time, the quality requirements for insulating glass are getting higher and higher. It is understood that the biggest quality problem of insulating glass is the condensation of the air layer during use, and the reason for the condensation of the air layer is that the dew point of the air layer increases during use. Therefore, controlling the dew point of insulating glass is the key to controlling the quality of insulating glass.
During the use of insulating glass, when the ambient temperature drops to the point where the glass surface temperature drops to the dew point in the dry air layer, condensation or frost will occur on the surface of the dry air layer. The performance of insulating glass is affected by condensation or frost on the inner surface of the glass. If it is ensured that the air layer does not condense above minus 40 degrees Celsius, there will be no air layer condensation during use of the insulating glass.
The dew point of insulating glass refers to the temperature when the air humidity sealed in the air layer reaches a saturated state. Below this temperature, water vapor in the air layer condenses into liquid water. It can be deduced: the higher the water content, the higher the dew point temperature of the air. When the temperature of the inner surface of the glass is lower than the dew point of the air in the air layer, the moisture in the air will condense or frost on the inner surface of the glass.
The dew point rise of insulating glass is caused by external moisture entering the air layer and not being absorbed by the desiccant. Three reasons may cause the dew point to rise:
(1) There are bubbles in the sealant, causing air moisture to enter.
(2) Water vapor diffuses into the air layer through the polymer.
(3) The effective adsorption capacity of the desiccant is low.
Measures to avoid quality problems
(1) Strictly control the production environment temperature
The production environment mainly affects adhesion capacity and remaining adsorption capacity.
(2) Reduce the diffusion of moisture through the polymer
It mainly relies on selecting a sealant with a low permeability coefficient, determining a reasonable sealing thickness, and reducing the temperature difference between the inside and outside of the insulating glass (that is, controlling production within a certain temperature range without making the temperature range too large).
(3) Reduce production process time
Minimize the time the desiccant is in contact with the atmosphere, reduce the loss of adsorption capacity, and make the desiccant have higher adsorption capacity.
(4) Choose the appropriate aluminum profile
The air guide gaps of its pores should be small to reduce the water absorption rate of the molecular sieve during operation.
(5)Choose the appropriate desiccant
Choose a desiccant with a high adsorption rate and long durability.
I believe that through the control of material selection, processing, environment and other aspects, the quality of insulating glass will be clearly controlled.
